<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
    <style>
        body{
            margin:0;
            padding:0;
            width:100%;
            height:100%;
            min-height:100%;
        }
        #container{
            position:relative;
            width:80%;
            margin:0 auto;
            min-height: 800px;
        }

        .Center-Container.is-Inline {
            text-align: center;
            overflow: auto;
            border:1px solid red;
            width:100%;
            height:500px;
        }

        .Center-Container.is-Inline:after,
        .is-Inline .Center-Block {
            display: inline-block;
            vertical-align: middle;
        }

        .Center-Container.is-Inline:after {
            content: '';
            height: 100%;
            margin-left: -0.25em; /* To offset spacing. May vary by font */
        }

        .is-Inline .Center-Block {
            background:#ccc;
            width:400px;
            max-width: 99%; /* Prevents issues with long content causes the content block to be pushed to the top */
            /* max-width: calc(100% - 0.25em) /* Only for IE9+ */
        }
    </style>
</head>
<body>
<div id="container">
    <div class="Center-Container is-Inline">
        <div class="Center-Block">
            <!-- CONTENT -->fdas
        </div>
    </div>
</div>
</body>
</html>